Abnormalities of megakaryocytes in myelitis and chronic myeloproliferative diseases

In Vitro Megakaryocyte Differentiation and Proplatelet Formation in Ph-Negative Classical Myeloproliferative Neoplasms: Distinct Patterns in the Different Clinical Phenotypes

“…Of particular interest, we found that megakaryocytes from both pre-fibrotic and fully fibrotic PMF produce less proplatelets than normal. This finding underscores the biological diversity of prefibrotic PMF and ET, and supports the distinction between these two nosological entities, which has been proposed on the basis of bone marrow morphology [28]–[30] but has not been universally accepted yet [26].…”

“…These data suggest that other, yet-unknown, genetic mutations may contribute to altered megakaryopoiesis in MPNs [18]–[22]. Interestingly, PMF megakaryocytes were smaller than those of other MPN or of CTRL: these findings are in keeping with the well known morphological alterations of megakaryocytes that can be observed in bone marrow biopsies, which represent a key element for the diagnosis of the different types of MPN [23]–[26], [28]–[30]. Most importantly, our results could be correlated with recent data by Besancenot et al that claimed that malignant megakaryocytes undergo abnormal proliferation by escaping the phisiological mechanisms of cell cycle arrest and senescence induced by TPO signalling [27].…”

Interferon‐alpha‐induced morphological changes of megakaryocytes: a histomorphometrical study on bone marrow biopsies in chronic myeloproliferative disorders with excessive thrombocytosis

“…1985Ludwiget al, 1987: Gisslinger et al, 1989 and to improve previously impaired platelet functions (Ludwig et al, 1987). Besides the expected result of platelet decimation-probably due to shortened half-life, changes in aggregation and other func- an intense primary effect on megakaryopoiesis, but the number of our observations is too small to allow conclusive statements about dosage-related changes Megakaryocytes in CMPD have been reported to show bizarre shapes and irregular outlines (Wittels, 1985: Burkhardt et al, 1986) as compared to the more or less spheroidal shape encountered in normal controls (Thiele et al, 1982). During rIFN-alpha-2c treatment, the circular deviation factor increased in the entire patient group indicating a closer approximation to a circular outline.…”

“…Previous studies on megakaryocyte morphology have revealed some characteristic, but not entirely specific morphological alterations in CMPD-megakaryocytes (Lagerlof, 1972: Branehog et aZ, 1975Thiele et al, 1982). The described differences between the distinct subgroups of CMPD may even serve as an additional diagnostic tool, if bone marrow biopsies are available (Thiele et aZ, 1984(Thiele et aZ, , 1988.…”

“…The degree of aberration from a circular circumference was calculated for each megakaryocyte. This circular deviation factor (Thiele et al, 1982) is derived from the geometric characteristics of a circle (47-c x area divided by circumference? = 1.00) and assesses a more ellipsoid outline or an increased irregularity of shape by values smaller than 1 .OO.…”